Insulated electrical conductor



Nov. 22', 1927. 1,649,924

Y F. L. ROMAN ET AL INSULATED ELECTRICAL CONDUCTOR Filed Dec. 12 1925 Patented Nov. 22, 1927.

UNITED STATES PATENT OFFICE,

FRANK LOUIS ROMAN, OF CHICAGO, AND HARRY THOMAS WINSEMIUS, OF CONGRESS PARK, ILLINOIS, ASSIGNORS TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. 'Y., A CORPORATION OF NEW YORK.

INSULATED ELECTRICAL CONDUCTOR.

Aiiblication filed December 12, 1925. Serial No. 75,011-

This invention relates to insulated electrical conductors, and more particularly to electrical conductors provided with so-called flame-proof insulation.

The object of the present invention 1s the provision of an electrical conductor w th an inexpensive and efficient flexible covering of flame-proof electrical insulation.

In order to attain this object there is pro vided in one embodiment of the invention, an electrical conductor in wire form having a coating of suitable insulating enamel covered with acotton serving impregnated with chlorinated naphthalene to reduce its 1nflammability, and with an. outer braided covering of cotton which is also preferably fiame-proofed.

Other objects and features of the 1nvention will be apparent from the following detailed description and the accompanying drawing which shows an insulated wire embodying one form of the invention.

In accomplishing the invention, an electrical conductor such as a tinned copper wire is covered with a fibrous material whiclris impregnated with a. halogenated material such as chlorinated naphthalene. The 1nvention may take a variety of forms, an embodiment of which is shown in the accompanying drawing, in which the numeral 10 refers to a metallic conductor and 11 1s a coating of insulating material such as the usual enamel. Over the enamel 11 is placed a serving or servings 12 of textile material,

preferably cotton, which is impregnated withchlorinated naphthalene or other halogenated material in a manner which will be described more in detail hereinafter, On

the outside of the serving 12 is a flame-proof braided covering 13, preferably braided cotton, which has been treated with ammonium phosphate to decrease its inliammability.

In impregnating the textile covering 12 various types of halogenated material may be employed, but uniformly good results have been obtained in producing an insulated conductor in accordance with this invention by the use of a grade of chlorinated naphthalene which is marketed under the trade name of halowax. In using the chlorinated naphthalene, if a comparatively refined compound is employed, it is preferable that it be mixed with a comparatively small amount of a. bituminous material. preferably refined coal tar, to increase its adhesiveness. Good results are also obta ned by employing crude chlorinated naphthalene generally termed crude halowaX or halowax pitch and about 5% of refined coal tar. Other types of halogenated materials which may be used in the practice of the invention are bromonaphthalene or other materials related to naphthalene, such as anthracene or coal tar treated with one of the halogens.

After the serving 12 has been placed on the enamel 11 in either a single layer or a plurality of layers, the conductor is passed through a bath of melted halogenated material to obtain a thorough impregnation of the serving. The serving 12 may be silk, cotton or other textile strand, but on account of the lower price of cotton and since it has good electrical insulating characteristics when employed in connection with the present invention, this material is preferred.

The insulated conductor may be employed without the braided covering 13, but this covering improves the appearance of the conductor and serves to protect the other insulation from abrasion, and for these reasons in most cases will probably be employed. Any type of braided covering may be used but in its preferred form it consists of braided cotton which has previously been treated with a flame-proofing material such as ammonium phosphate.

An insulated conductor produced accord ing to the present invention is of great value because it is quite resistant to burning, possesses good electrical characteristics, and in addition is economical to manufacture. Another advantage where an enameled conductor is employed, is that the chlorinated material has a tendency to somewhat soften the enamel making it readily removable for the purpose of soldering or otherwise, and at the same time not affecting the insulating value of the enamel. This softening eifect of the enamel is not sufficient to in any way dissociate it from the conductor, since it is retained iii-place by the cotton serving or other insulation, which in the practice of the invention is applied over it. Still another advantage resulting from the use of chlorinated naphthalene is that this material will not interfere with soldering operations should it in any way come in contact with the bare wire which is to be subjected to a soldering operation.

What is claimed is:

1. An insulated wire comprising an electrical conductor having a coating of fibrous material treated with a halogenated material.

2. An insulated wire comprising an electrical conductor havin a coating of insulating material treate with a mixture of chlorinated naphthalene and a bituminous material.

3. An insulated wire comprising an electrical conductor having a textile insulatin covering impregnated with chlorinate naphthalene.

4. An insulated wire comprising an electrical conductor, a serving of cotton impregnated'with a halogenated material, and a braided covering of cotton treated with a flame-proofing material.

5. An insulated wire comprising an electrical conductor, a serving of cotton impregnated with chlorinated naphthalene, and a braided covering of flame-proofed cotton.

6. An insulated wire comprising an electrical conductor coated with Insulating v enamel, a' cotton serving around the enamel impre nated with a halogenated material, and a raided outer covering of cotton treated with a flame-proofing material.

7. An insulated wire comprising a core covered with an insulating enamel, a cotton serving impregnated with a. mixture of chlorinated naphthalene and a relatively small amount of a bituminous material, and 

